We propose to continue our studies on the basic organic chemistry of ozone and the relationship of that chemistry to environmental health with particular emphasis on mutagenesis and carcinogenesis. Our specific aims include studying basic ozone chemistry and the chemistry of the ozone-derived oxidants, carbonyl oxides and dioxiranes. PAH's absorbed on model particulates will be exposed to a gas stream containing: 1) ozone and 2) an ozone-alkene reaction mixture. Differences in product distributions in these two types of reactions will indicate reactions between the PAH's and ozone-derived oxidants. The presence of arene oxides in the ozone-alkene experiments could be related to the production of mutagens/carcinogens in polluted atmospheres. The nature of the responsible oxidant (carbonyl oxide or dioxirane) will be determined. Ozonolysis of solutions of tetra-substituted alkenes at varying concentration will be studied for evidence of dioxirane formation. Improved methods for the synthesis of dioxiranes will be sought. The reactions of dioxiranes with saturated hydrocarbons will be studied under a variety of reaction conditions. Solvent effects on the rate of epoxidation by dioxiranes will be measured.